Newsprint and other forms of paper are manufactured and processed as large elongated sheets or webs. As shown in FIG. 1 (Prior Art), for storage and transport, the paper stock is wrapped around a core to form a cylindrical roll, a step known as winding (FIG. 1A). To protect the roll and avoid spoilage of the paper, e.g. by the moisture, the atmosphere, and/or physical abrasions, the roll itself is wrapped in a protective wrapping (FIG. 1B) which can be moisture proof. Specialized machinery is employed to automatically apply the wrapper to the large rolls. Typically, the rolls are then stacked one on the other and stored on end.
Various methods have previously been used to wrap paper rolls. One of the most successful methods has been to first wrap the roll in one or two layers of a protective wrapper (FIG. 1B), with the wrapper extending outwardly beyond the ends of the roll. Next, interior roll headers (disks formed of corrugated board, chipboard, coated chipboard, laminated kraft paper or recycled paper) are fitted inside the wrapper against the ends of the roll (FIG. 1C). The wrapper is then crimped over the edges of the interior headers at the ends of the rolls using a crimping wheel or any other appropriate technique (FIG. 1D).
A set of exterior or outside roll headers (disks typically formed of a recycled paper or a kraft paper with a polymer coating on the inside surface) are then attached to the ends of the roll over the crimped edges (FIG. 1E). The headers and the wrapper are held in place and affixed to one another through the use of an adhesive, such as a heat-sensitive adhesive (a polymer coating), on the inside surface of the exterior roll header and/or the outward face of the interior roll header. The exterior roll headers are affixed to the ends of the rolls in a typical roll wrapping machine by applying heat and/or pressure in accordance with the properties of the adhesive used. To heat seal the headers, pressure and high temperature are usually necessary.
Standard polymer coating which are applied to the inside surface of the exterior headers include low density polyethylene (LDPE) coatings. Upon heat sealing these headers at high temperature, one can observe generation of toxic gas such as volatile organic compounds (VOCs) and carbon monoxide, which may raise safety and environmental concerns.
In view of the above, there is a need for headers for packaging paper rolls which would be able to overcome or at least minimize the above-discussed prior art concerns.